Current version of imagify can only work on Linux, due to `export` syntax of `texinputs`

[bastienchassagnol]

At this line, using export on a Windows OS environment is likely to generate the following error, @jdutant :

'export' n'est pas reconnu en tant que commande interne
ou externe, un programme ex�cutable ou un fichier de commandes.
[ERROR] Imagify: LaTeX compilation failed.
Command used: export TEXINPUTS=C:\Users\basti\OneDrive\04. BNCL (Post Doc)\Open-Source Development\open-source-quarto-reprex//:C:\Users\basti\AppData\Local\Temp\quarto-session301b8827eb8a66d9\2bcb0c5df16020d3//:C:\Users\basti\OneDrive\04. BNCL (Post Doc)\Open-Source Development\open-source-quarto-reprex//:; latexmk  -xelatex --interaction=nonstopmode source.tex

Consider the Windows OS case:

env = 'set TEXINPUTS=' .. texinputs .. '&& '

Examples drawn from quarto-cli:

• Quarto definition of variables